Hi, Dan
When you discuss this with your doctors (and they don't say no due to the infection risk), you might ask about going with the PEG early on so that if the swallowing does hit you hard, it will be in place, allowing you to maintain your weight level and avoid any drama of getting the PEG in on your way to the airport. You don't have the spare weight to lose.
My husband went back to work 5 days after his last rad. He could probably have managed what you are contemplating, but looked less than chipper, and had problems talking due to the sore mouth, throat and thick mucous. Two weeks made a huge difference with him - if the second wedding were just a bit later it would help. We're all rooting for you, however it goes!